DESCRIPTION: The effects of lead and carbon disulfide on the measurement of cognitive and sensory function will be assessed using a chick model. Specific aims include determination of: a) ability to detect low-level sound, b) discriminate small differences between similar sounds, and c) pattern perception will be used to resolve deficits in auditory/cognitive function following in ovo exposure to lead and carbon disulfide. It is anticipated that data derived from the proposed studies will provide preliminary data for a subsequent submission aimed at quantification of critical periods of exposure and synergistic effects with other environmental insults such as noise and toxicants.